1. The Field of the Invention
This invention relates to cargo transporting and, more particularly, to novel systems and methods for unloading material from a cargo area.
2. The Background Art
Many materials such as sand, gravel, dirt, and grain are commonly transported in pickup trucks, trailers, and the like. Other bulk materials commonly transported include trash, yard waste, manure, mulch, bark, building materials, hay, feed, firewood, equipment, tools, palletized materials, and the like. These materials are generally loaded in bulk at a distribution point by a front-end loader, overhead bin, forklift, or the like. Thus, loading of the material into the cargo area of a vehicle is generally accomplished without much effort.
The same does not hold true, however, for unloading the materials from vehicles. Unloading usually takes place at a jobsite, the vehicle owner's home or yard, or other place where unloading must be accomplished by physical labor. Generally, this means using a shovel to unload granular or other bulk materials or physically manhandling equipment type items from the front of the cargo area where they are generally placed for the best load distribution, to the rear of the cargo area where they may be off-loaded. Unloading in this manner is labor intensive, time consuming, and dangerous due to the manual labor involved and the requirement that the unloader climb on top of the load.
One method employed to solve these problems is to tilt the cargo area up at an angle utilizing gravity to off-load the material such as shown in the inventor's patent U.S. Pat. No. 6,267,448. Many such apparatus require major modifications to the vehicle. Those that use a hydraulic cylinder to do the dumping have required the bed to be raised destroying the cab to body lines and the looks of the truck. Even the hinge system in the inventor's U.S. Pat. No. 6,059,371 may be expensive and require modifications to the vehicle to hinge the cargo area or truck bed to allow the load to be dumped.
Another method that has been used to remove a load from the cargo area is shown in U.S. Pat. No. 49,006. This method utilizes a jointed conveyor of slats that is narrower than the width of the cargo area. The conveyor is pulled out by winding a cord attached at the front of the conveyor slats around a roller at the rear of the cargo area. Often, such designs require that the roller be rotated by a hand crank.
Another variation is shown in U.S. Pat. No. 5,340,266. In this patent, a flexible material is pulled out of the bed as it wraps around a roller that is rotated by a manually driven crank. Others have replaced the manual crank with a motor drive system such as shown in U.S. Pat. No. 4,629,390. Another method is shown in U.S. Pat. No. 6,131,983, wherein a liner is fitted to the bed of a truck and includes pockets for the wheel wells and straps on the front that may be pulled rearward by hand to roll the load out onto the ground.
Each of the foregoing devices is either costly to manufacture, manually powered, limited in maximum capacity, dependent on extensive modifications to the vehicle, or the like. What is needed is a inexpensive system that is easy to operate and requires little or no modification to the vehicle.